Oil loss

[LEETR4A]

Hi all

 

My 4A has been on the road for a year now after a total rebuild and has always vented a small amount of oil from the oil filler cap even though the flame trap was removed and a breather pipe added from the rocker cover.

After the run back to London from the Isle of Wight a couple of weeks ago the car lost over three pints of oil which I found had come out of the dip stick hole. The same happened again yesterday after an eighty odd mile run.

Is there too much pressure build up in the engine (oil pressure reads around 50-60 when hot)?

There is an extra oil feed fitted to the cylinder head and the car has covered 1500 miles since going back on the road.

Do I need to fit an extra breather or is there something more fundemental wrong.

 

Thanks in advance

Lee

[Ade-TR4]

I'd probably remove the extra oil feed.

 

They can deliver too much oil to the top of the engine, potentially starving the bottom-end.

 

The excess oil up-top may be clogging the breather and causing the crank-case to vent via the dip-stick.

 

Did you vent the crank-case when you ditched the PCV thing? (ie early style breather?)

 

Cheers

Adey

[Tr4Tony]

Lee

 

This is almost certainly due to excess crank case and block oil pressure which is driving your oil out through the path of least resistance ...... as youve seen.

 

The solution is to vent both the rocker cover and block to a catch tank. The rocker cover is easy as Adey says, the block you need to vent through the welsh plug below the fuel pump, where on early engines there was a venting tube ..... but the system needs to be sealed, with venting at the catch tank only to avoid oil loss during cornering.

 

Regards

 

Tony

 

 

 

I'd probably remove the extra oil feed.

 

They can deliver too much oil to the top of the engine, potentially starving the bottom-end.

 

The excess oil up-top may be clogging the breather and causing the crank-case to vent via the dip-stick.

 

Did you vent the crank-case when you ditched the PCV thing? (ie early style breather?)

 

Cheers

Adey

[ianc]

How have you routed the "breather pipe added from the rocker cover"?

If it comes out of the side of the rocker cover and then heads directly for the ground, I think you'll be expelling buckets of oil down the tube.

I suggest you take the tube upwards to the level of the top of the rocker cover before heading downwards. In my case (TR4), the tube comes out of the right side of the alloy rocker cover (towards the carbs), so I have connected a rubber hose which goes over the top of the rocker cover and then down, past the fuel pump, to end alongside the crankcase vent. On the TR4A, there's no crankcase vent, but you could finish at about chassis level on the left side. I have a feed to the rockers, but very little (other than some water vapour) comes out of this extra vent.

Ian Cornish

[Badfrog]

Lee,

 

As Adey said, remove the rocker feeder. very inappropriate gizmo.

Check that thread in TR4 forum: "Complete loss oil systems" launched by Teqwin. Some possibly useful info for you.

 

Badfrog

Edited May 18, 2009 by Badfrog

[LEETR4A]

Hi all

 

Thanks for the replies.

The rocker cover feed rises before it goes down over the carbs and exits by the front chassis cross member.

I have checked the end of the pipe and there is no sign of oil loss from there.

I also blew through the pipe and there are no blockages.

I take it that the welsh plug you refer to TR4Tony is the core plug under the fuel pump rather than the small bolt that I have used as the feed to the rocker cover.

I will start by removing the oil feed as you suggest and then look at fitting an oil catch tank with the crank case breather.

Let's hope it solves the problem.

 

Regards

Lee

[rclo]

Hi all

 

My 4A has been on the road for a year now after a total rebuild and has always vented a small amount of oil from the oil filler cap even though the flame trap was removed and a breather pipe added from the rocker cover.

After the run back to London from the Isle of Wight a couple of weeks ago the car lost over three pints of oil which I found had come out of the dip stick hole. The same happened again yesterday after an eighty odd mile run.

Is there too much pressure build up in the engine (oil pressure reads around 50-60 when hot)?

There is an extra oil feed fitted to the cylinder head and the car has covered 1500 miles since going back on the road.

Do I need to fit an extra breather or is there something more fundemental wrong.

 

Thanks in advance

Lee

Lee

 

Check you have rebuilt the breather unit correctly. If you get the spring and the diaphragm in the wrong order you get that symptom. I did it in mine by accident and the dipstick almost blew itself out. Don't ask me why but swopping the components solved theproblem. If i get to the next NLG meet I will speak to you then.